Zhang Xinai, Geng Ping, Liu Huijie, Teng Yingqiao, Liu Yajun, Wang Qingjiang, Zhang Wen, Jin Litong, Jiang Lai
Department of Chemistry, East China Normal University, Shanghai 200062, PR China.
Biosens Bioelectron. 2009 Mar 15;24(7):2155-9. doi: 10.1016/j.bios.2008.11.019. Epub 2008 Dec 3.
A sensitive electrochemical immunoassay for rapid detection of Escherichia coli has been developed by anodic stripping voltammetry (ASV) based on core-shell Cu@Au nanoparticles (NPs) as anti-E. coli antibody labels. The characteristics of Cu@Au NPs before and after binding with antibody were confirmed by transmission electron microscopy (TEM). After Cu@Au-labeled antibody reacted with the immobilized E. coli on Polystyrene (PS)-modified ITO chip, Cu@Au NPs were dissolved by oxidation to the metal ionic forms, and the released Cu(2+) ions were determined at GC/Nafion/Hg modified electrode by ASV. The utilization of GC/Nafion/Hg modified electrode could enhance the sensitivity for Cu(2+) detection with a concentration as low as 9.0 x 10(-12)mol/L. Since Cu@Au NPs labels were only present when antibody reacted with E. coli, the amount of Cu(2+) directly reflected the number of E. coli. The technique could detect E. coli with a detection limit of 30CFU/mL and the overall analysis could be completed in 2h. By introducing a pre-enrichment step, a concentration of 3CFU/10mL E. coli in surface water was detected by the electrochemical immunoassay.
基于核壳结构的铜@金纳米颗粒（NPs）作为抗大肠杆菌抗体标记物，通过阳极溶出伏安法（ASV）开发了一种用于快速检测大肠杆菌的灵敏电化学免疫分析法。通过透射电子显微镜（TEM）确认了铜@金纳米颗粒与抗体结合前后的特性。铜@金标记的抗体与固定在聚苯乙烯（PS）修饰的ITO芯片上的大肠杆菌反应后，铜@金纳米颗粒通过氧化溶解为金属离子形式，释放出的铜（2+）离子在GC/纳夫ion/汞修饰电极上通过ASV进行测定。使用GC/纳夫ion/汞修饰电极可提高对低至9.0×10（-12）mol/L浓度的铜（2+）检测的灵敏度。由于只有当抗体与大肠杆菌反应时才存在铜@金纳米颗粒标记物，铜（2+）的量直接反映了大肠杆菌的数量。该技术能够检测大肠杆菌，检测限为30CFU/mL，整个分析可在2小时内完成。通过引入预富集步骤，电化学免疫分析法检测到地表水中大肠杆菌的浓度为3CFU/10mL。
